From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: [PATCH 1/9] pci-assign: Optionally enable 64bit BARs in guest Date: Tue, 31 Jan 2012 13:45:14 +0100 Message-ID: <4F27E25A.1060306@siemens.com> References: <20120128142104.25681.93072.stgit@bling.home> <20120128142139.25681.19080.stgit@bling.home> <4F27E15A.1090800@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Alex Williamson , "kvm@vger.kernel.org" , "shashidhar.patil@gmail.com" To: Avi Kivity Return-path: Received: from thoth.sbs.de ([192.35.17.2]:24512 "EHLO thoth.sbs.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752242Ab2AaMpT (ORCPT ); Tue, 31 Jan 2012 07:45:19 -0500 In-Reply-To: <4F27E15A.1090800@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 2012-01-31 13:40, Avi Kivity wrote: > On 01/28/2012 04:21 PM, Alex Williamson wrote: >> To date we've only exposed BARs as 32bit even if the device >> physically supports 64bit BARs. Enable 64bit BARs to be >> exposed as such in the guest, which may free up MMIO below >> 4G should the guest choose to use it. >> >> This adds a new mem64= option to pci-assign, with the >> default being off for testing and enablement. The goal >> is to eventually make this enabled by default. >> > > Seems fine, but do we really need the option? If it doesn't work we > should treat it as an ordinary but and fix it. So far it's against the architecture of the emulated system: our current chipset predates 64 bit PCI. Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux